
CHI SQUARE TWO SAMPLEName:
Dataplot supports the chisquare two sample test for either binned or unbinned data. For unbinned data, Dataplot automatically generates binned data using the same rule as for histograms. That is, the class width is 0.3*s where s is the sample standard deviation. The upper and lower limits are the mean plus or minus 6 times the sample standard deviation (any zero frequency bins in the tails are omitted). Note that the binning computations are performed with the combined data set. As with the HISTOGRAM command, you can override these defaults using the CLASS WIDTH, CLASS UPPER, and CLASS LOWER commands. The quantilequantile plot, bihistogram, and Tukey meandifference plot are graphical alternatives.
where <y1> is the first response variable; <y2> is the second response variable; and where the <SUBSET/EXCEPT/FOR qualification> is optional. This syntax is used for unbinned data.
where <y1> is the first response variable; <y2> is the second response variable; <x> is a variable containing the midpoints of the bins; and where the <SUBSET/EXCEPT/FOR qualification> is optional.
This syntax is used for binned data. The
CHISQUARE TWO SAMPLE TEST Y1 Y2 X CHISQUARE TWO SAMPLE TEST Y1 Y2 X SUBSET Y2 > 0
LET A = TWO SAMPLE CHI SQUARE TEST CDF Y1 Y2 LET A = TWO SAMPLE CHI SQUARE TEST PVALUE Y1 Y2 In addition to the above LET command, builtin statistics are supported for about 20+ different commands (enter HELP STATISTICS for details).
CHISQUARE TWO SAMPLE TEST CHI SQUARE 2 SAMPLE TEST CHISQUARE 2 SAMPLE TEST TWO SAMPLE CHI SQUARE TEST TWO SAMPLE CHISQUARE TEST 2 SAMPLE CHI SQUARE TEST 2 SAMPLE CHISQUARE TEST The word TEST in the above commands is optional.
SKIP 25 READ AUTO83B.DAT Y1 Y2 DELETE Y2 SUBSET Y2 < 0 . SET WRITE DECIMALS 5 CHI SQUARE TWO SAMPLE TEST Y1 Y2The following output is generated. ChiSquare Two Sample Test First Response Variable: Y1 Second Response Variable: Y2 H0: The Two Samples Come From the Same (Unspecified) Distribution Ha: The Two Samples Come From Different Distributions Sample One Summary Statistics: Number of Observations: 249 Sample Mean: 20.14457 Sample Standard Deviation: 6.41469 Sample Minimum: 9.00000 Sample Maximum: 39.00000 Sample Two Summary Statistics: Number of Observations: 79 Sample Mean: 30.48101 Sample Standard Deviation: 6.10771 Sample Minimum: 18.00000 Sample Maximum: 47.00000 Number of NonEmpty Cells: 18 Class Width For Bins: 1.83231 Lower Class Limit: 38.48819 Upper Class Limit: 58.63277 ChiSquared Test Statistic: 35.65477 Degrees of Freedom: 18 CDF of Test Statistic: 0.99219 PValue: 0.00780 Conclusions (Upper 1Tailed Test)  Null Hypothesis Null Null Confidence Critical Acceptance Hypothesis Hypothesis Level Value (>) Interval Conclusion  Same 50.0% 17.33 (0,0.500) REJECT Same 80.0% 22.75 (0,0.800) REJECT Same 90.0% 25.98 (0,0.900) REJECT Same 95.0% 28.86 (0,0.950) REJECT Same 97.5% 31.52 (0,0.975) REJECT Same 99.0% 34.80 (0,0.990) REJECT Same 99.9% 42.31 (0,0.999) ACCEPT  
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Date created: 06/05/2001 